"Intellectual Property" is not, or at least should not, be the same as physical property. Copyrights and patents are temporary artificial, government enforced monopolies to incentivise creativity and publication of the results of that creativity. I don't think it's unreasonable to say that a corporation can't own the copyright itself. Although, they should still be able to hold a license to works from the actual human creators, and granting such a license could be a condition of employment (provided it was created as part of the employment, and not, say, on the employees own time).